Grace does much more abound Romans 5:20

You don't have to throw your hands up and quit because you committed a sin.  All you need to do is to go to the Lord in Prayer, confess to Him your sin, tell Him what you did,  call it by name, and He will forgive you, if you mean it from the dephts of your heart.  He won't only forgive you.  He will also cleanse you of the sin.  God loves you and wants to fellowship with you.  If you have sin in your life you can have no fellowship with God, nor Him with you.  So confess that sin(s) to God,ask Him to forgive you, and cleanse you. He will, and He will also bring you back into fellowship with Him.